Feeling unconfident and tierd/ fed up with running is fairly normal ( for me anyway). At this stage I usually struggle to drag myself out the door, but am panicking about poor preparation.
During the taper, the panic gets worse, and the desire to just do a "bit extra" gets more extreme. Relax ,you're over most of the hard work, just keep it ticking over, perhaps some shorter runs at race pace, after a few days rest, but don't fight your way through a 20miler if it is going to be a horrible sonfidence- sapping drag- I suspect you need rest more than a long run just now.
I have stopped to tape "hot spots" during marathons and ultras- you need- wet wipes to clean your feet- tape that agrees with you, and sticks well, and fresh socks to put on after if possible.You MUST try it out before, though Micropore works well for me, - sticks well on clean dry feet without tinc benz, but I've never tested it with really wet conditions, or over more than 57miles.
Unless you are very flexible there isa a reall risk of getting cramp trying to get to your feet- you might get lucky and find a helpful "foot fixer" at an aid station, but don't rely on them.
Managed a 20 today, and not feeling too bad with it. This is on top of 2 hours out in the monsoon on thurday - managed to navigate from yorkhill, up the kelvinwalkway ( via large parts of the path being under fairly deep water/ various diversions for subsidence)), to maryhill lochs, and onto the forth and clyde canal- bit dodgy in parts, that route, but perhaps I can do it again next weekend, and actually get onto the start of the Glasgow to Edinburgh route!.
Planning another 20 miler next weekend, if the oncall doesn't damage me too much, then the LK 1/2 and taper for the Glasgow to Edinburgh- still worried about mileage before the double, but not sufficiently worried to pull out- maybe I'm being stupid, we'll see!
Ski- ing as training? - not really the way we do it ( on the slopes by lunch time- 3 hrs sclepping around the blue runs, and off to the pub at 4pm!). OK . so we were at altitude, which might count for something, but we ate and drank like there's no tomorrow, so have 1/2 a stone extra, which is slowly coming off!
CD- I like the idea that for an experienced marathon runner, there isn't much point in doing loads of runs longer than 2:30- 3hrs. I'm slow ( 4:15-20), but have done a number of marathons where I do a lot of 11miles back -to back days ( running commute 11 miles home form work, then back the next day), and only a handful of runs over 3hrs, with very few 20milers. I've also done a couple of short ultras, I don't find it a big problem. The 5x20 milers are aimed at the faster end of the market, I'm sure!
It is definitely useful to get to 20 miles before your first marathon, once or twice if you can, as it feels vaguely familiar on race day, but knackering your self will not help.
Don't try anything new on race day- lots of people find that lucozade or Gels give them stomach problems. If a banana at half way is what suits you, the only challenge is how to carry it without it getting squished.
Water is by far the easies drink to use, and all you need for a half, don't be tempted to start gulping down all sorts of sugary stuff unless you really need it.